Resilient cushion and method of manufacture



RALPH H. JACKSON DONALD VAN WAGENEN R. H. JACKSON ETAL Filed June 28, 1955* RESILIET CUSHION AND METHOD OF MANUFACTURE Aug. 9, 1960 lnited States Patent O RESILIENT CUSHION AND METHOD or MANUFACTURE v t Filed June 2s, 1955ser. No. 518,632

s claims. (cl. 154-100) This invention rel-ates to an improved resilient cushion material and to a method for its manufacture.

Rubberized curled hair is a commercially available product Ythat is commonly used as a cushioning material, especially in the furniture industry for upholstering. Most applications require that some shield be placed between the curled hair and the upholstering fabric. This is necessary to prevent the hair ends from protruding through the fabric. The conventional shielding material employed is a layer of cotton batting. More recently, however, resilient foam material such as rubber and other plastics has been employed as shielding in the form of a thin layer cast upon the hair.

The advantage of casting a foam layer on the curled hair surface, as an integral part of the pad, is the elimination of the extra operations in upholstering of vadding the shielding material. Several difficulties arise in casting a foam in the form of a thin sheet directly on to curled hair. Due to the open structure and irregular surface of the curledhair some of the foam .penetrates into the curled hair mass and its shielding effect is lost. Therefore, `a uniform foam surface and thickness is not obtained and often individual hairs sticking up from the curled hair mass protrude through the foam surface. Another shortcoming of a cushion in which the foam is applied directly to a hair pad is that compression of such a cushion results in an undesirable noise caused by the scraping of hair ends. against the foam layer interface.

It is, therefore, an object of the present invention to provide animproved hair-foam cushioning material not subject to the above mentioned shortcomings and diiculties.

It is a further object of this invention to provide a process for producing a hair-foam cushioning material which has a smooth, uniform surface and thickness ofl foam shielding.

Further and additional objects of this invention will become apparent from the following specification and the accompanying drawings in which:

Figure l is a sectional view of our improved hairfoam cushioning material;

Figure 2 is a partial diagrammatic view of a produc- :tion line for producing hairfoam cushioning material; :and

Figure 3 is the rest of the production line of which :the first portion is shown in Figure 2.

In accordance with the present invention, rubberized curled hair is produced in a continuous web. Before curing this web a loosely woven fabric, such as cheese- Lcloth, is laid upon the surface of the curled hair web. 'This fabric gives a relatively smooth surface on which :a foam layer is doctored. As the foam vis highly viscous :as spread, very little penetrates the fabric. After the oam is doctored on to the fabric, the resulting laminate is cured in a vulcanizing oven.

The hair'used as a starting material in accordance with,

the present invention includes the common types of '2,948,650 Patented Aug. 9, 1960 ICC commercial animal hair, such as horse hair, cattle hair, yand -hog hair. Specifically desirable types of hair from both an economic and functional standpoint are rel-atively short hairs, such as hog hair and cattle body hair. However, long types of hair, such as cattle tail hair, horse mane hair, etc. can be employed. Excellent results are obtained with hog hair which can contain a percentage of other types of hair, such as cattle tail hair. The hair filaments employed preferably have a three-dimensional curvature `impressed upon them by a curling process. For example, the hair can be curled by the well known mechanical curling process, or it can be curled by the more recently developed chemical curling processes. It is not absolutely necessary that curled animal hair be exclusively employed, although thisV isdesirable. Synthetic fibers or fibers of vegetable origin can be used.

As indicated above, the curling of hair by either mechanical or chemical processes introduces a threedimensional curl in the hair filaments so that a random distribution of the hair on a flat surface produces an approximate stereoreticulate mass thereon which will produce a hair web of approximately the same density for the same kind of hair having about the same degree of statistical curl. The curling of the hair is a well known process and does not constitute a part of the present invention. Processes and machines for effecting mechanical curling of hair are described in U.S. Patents Nos. 480,605, 1,658,813, and 2,529,647. Chemical processes for curling hair are described in U.S. Patents Nos. 2,261,094, 2,351,718 and 2,410,248.

The initial step in the production of hair pads involves` the spreading of the curled animal hair in a layer of the desired thickness. This can be accomplished either manually or mechanically, and preferably the hair is allowed to fall on a horizontal surface so that it assumes a random distribution and forms a hair mat or web of a predetermined bulk density. For the preparation of hair pads used in upholstering a hair web or mat between 1 to 2 inches is preferred.

Referring to Fig. 2 of the drawing, there is shown in somewhat diagrammatic form mechanical apparatus for carrying out the production of rubberized hair pad.

y The curled hair in hopper 10 is fed downwardly on to Hair spreader 12 also includes two lower spreading rolls 15 and 16. The fluffy mass of hair 17 is discharged downwardly by the carding rolls 13 and 14 and spreading rolls 15 and 16 on to a continuous conveyor belt 20 where it is formed into a web 18 of the desired thickness. Following 4the formation of t-he at hair mat or web, it is sprayed with an elastomer for the purpose of bonding the air filaments together. One or both sides of the web can be sprayed, and a plurality of spraying on both sides can be used if desired. With webs of about -1 to 2 inches in thickness, it has been found desirable to spray the web a single time from each side. This egives excellent penetration by the liquid elastomer dispersion and prevents the dispersion from collecting on tlhe conveyor or other supporting surface because t-he bottom half of the web acts as a lter duringeach spraying operation.

Referring again to Fig. 2 to the drawing, the web 18 is shownl being carried toward the right from hair spreader 12 by conveyor belt 20 to a spraying station or zone 21 wherein one side of the web is sprayed with the liquid elastomer dispersion. In the illustration given, there is shown a spray head22, which is preferably of lche oscillating type so that it moves back and forth across the web during the spraying operation. Suicientelastomer is applied to spray station 21 to penetrate the upper half of the web. takes the partially elastomer-coated web through a drying zone 23 wherein the elastomer coating is dried to an indispersible but unvulcanized condition so as Vto increase the tensile strength of the mat so that it can be inverted without tearing the mat, and also so that the elastomer coating will not drain downwardly upon the conveyor belt when the web is inverted and cause the web' to stick. Ordinarily, the time required in drying zone 23 will be between about 15 to 20 seconds when a dryer of the hot air blast type is employed. The partially coated web 18 is then taken over an inverter 24 which turns over the web so that the uncoated portion of the web or mat is now :uppermost on the conveyor 20. The mat is then conveyed through a second spraying zone 25 similar to spraying zone 21. IIf desired, it can be equipped with oscillating spray head 26 of the same type as spray head 22. Sufficient elastomer is applied in spray station 25 to penetrate to Ithe center of the web and thus complete the distribution of the elastomer throughout the web.

When elastomer is applied by spraying as preferred, it is found that not only are the individual filaments coated with films or sheaths of the elastomer, but also that the elastomer tends to accumulate at the cross-points or intersections of the hair filaments and to form nodules which effectively lock the hair filaments together. Both the distribution of the elastomer on the hair filaments and the forming of nodules at the intersections of the hair filaments is desired, but it is believed that the nodules are of greater importance in imparting the desired mechanical properties to the hair mat.

Various types of elastomer dispersion can be employed. However, it is preferred to employ an aqueous dispersion of Aa vulcanizable elastomer. The specific elastomer employed can be either a natural rubber latex, a synthetic elastomer latex, or a reclaimed rubber dispersion. The rubber or synthetic elastomer dispersion is compounded with well known ingredients to facilitate the application and curing of the elastomer. Water may be added to secure the required consistency for application. Specific examples of elastomers which can be employed include natural rubber, butadiene-styrene dispersions, Neoprene rubber dispersions, etc.

In Fig. 3 of the drawing the completely impregnated web 18, after the completion of the operations illustrated in Fig. 2 of the drawing, is shown being carried into a drying zone 27. Here the web or mat is subject to less severe drying conditions than lthose described with respect to drying zone 23, so that the elastomer coating will emerge in a tacky but unvulcani'zed condition. As web 1S leaves drying zone 27, carried by means of conveyor belt 28, the upper exposed surface is in a tacky condi tion and thereby adapted due to the inherent adhesivity of the elastomer, to receive a layer of a loosely woven fabric, such las cheesecloth 30. 'Ilhe layer of hair and cloth are taken from conveyor belt 28 by means of an apron 31 and passed between two compression rolls 32 and 33 where the fabric and hair are compressed slightly to edectuate a bonding of the cheesecloth to the hair pad. The compression effected by rolls 32 and 33 is not sufficient to put any permanent set or compression in the hair pad but is merely sufficient to effectuate the bonding of the cheesecloth to the hair pad.

The hair pad-fabric laminate is passed over apron 34 on to a conveyor belt 35 where a layer of a viscous foam material 36 is applied on top of the fabric by means of a sprayer 37. The fabric 30 applied to the hair pad 18 is loose woven so that there is a slight penetration of the fabric by the foam 36. rllhis is to provide a better bonding of the foam to the fabric.

After application of the foam 36 to the fabric hair laminate, the foam is smoothed by means of doctor blade 38 and the resulting laminate allowed to proceed IImmediately thereafter conveyor belt 20 ialong conveyor 35 for a period of time suicient for the foam latex to gel. This usually occurs in a period of from 2 to 5 minutes. After the foam has gelled it is passed through a curing oven 40 where both the elastomer used to bond the hair fibers together and the latex foam applied to the fabric are cured. rIlhe temperatures obtaining in curing oven 40 are in the range of 260 F. to 290 F., and the operation is effected in about 40 to 60 minutes.

The resilient foam material employed as a shielding in accordance with the present invention can be a natural or synthetic latex foam or can be made of some of the more recent resilient plastic foams, as for example a polyurethane foam. The following are some examples b 11 Znc) diethyldithiocarbamate (supplied by R. T. Vanderi t o.

2Dithiocarbamate type ultra accelerator (supplied by R. T. Vanderbilt Co.).

8 Styrenated phenol antioxidant (supplied by R. T. Vanderbilt Co.).

4Zinc salt of mercaptobenzothiazole (supplied by R. T.

Vanderbilt Co.).

sFoam senstizer (supplied by Nuugatuck Chemical Co.).

The above components are continuously mixed with air in a machine, as the Oakes M14 continuous foamer, E. T. Oakes Corporation, and 5.00 parts of zinc oxide and 1.50 parts of sodium silicouoride added.

A typical flexible polyurethane foam can be formulated as follows:

Dry parts Selectrofoam 62011 100.00 Emulphor 4EL-7l9 2 0.20 Water 2.50 N-methyl morpholine 1.50 Hylene TM 3 40.00

1Polyester resin (supplied by Pittsburgh Plate Glass Co.).

2 Polyoxyethylated vegetable oil (supplied by Autara Clie1nicals Division of General Dyestuffs Corporation).

sToluene diisocyanate (supplied by E. I. du Pont de Nemours & Co.).

The above ingredients are intimately mixed giving a viscous liquid which starts foaming in about 15 seconds. After 20 to 30 minutes at room temperature the foam is sufficiently cured to permit handling.

Referring -to Fig. l of the drawing, there is shown in cross-section the laminate cushioning 4material of the present invention. It will be seen that a thin layer of foam rubber is bonded on a fabric which is in turn bonded to a hair pad.

While this invention has been described and excmpliiied in terms of its preferred embodiments, those skilled in the art will appreciate that modifications can be made without departing from the spirit and scope of this invention. For example, an alternate method for application of the cheesecloth is to lay it on the unsprayed surface of the inverted web at a point between drying zone 23 and spraying station 2S. At spray station 25 the elastomer dispersion can be sprayed into the hair mass through the cheesecloth. The web with the cheesecloth then passes into dryer 27 and through squeeze rolls 32 and 33.

An alternate method for curing is to pass the rubber foam-topped web into a steam filled chamber at atmospheric pressure for about 30 -to 40 minutes where curing is effected, and then into a drying chamber for to minutes where the hair mass and foam are dried at 180 to 220 F. Some of the foams which are included in the scope of this invention, as for example, the lexible polyurethane foams, do not require the curing conditions for natural or synthetic rubbers. These can be applied -to the web after curing oven and passed through a smaller oven for 5 to 10 minutes at 120 to 160 F.

We claim: Y

1. A continuous process for the production of 1hairfoam rubber cushion material which comprises spreading curled animal hair in an approximate stereo-reticulate mass in the form of a pad of substantially uniform thickness, partially dispersing through one surface of said pad a latex of a vulcanizable elastomer, drying the elastomer to a vulcanized condition, partially dispersing through the opposite surface of said pad a latex of a vulcanizable elastomer, drying the elastomer to a tacky but unvulcanized condition, applying a woven Yfabric to said opposite surface of said pad, continuously spreading and levelling a substantially homogeneous foam latex onto said fabric to form a layer of foam -rubber of desired thickness thereon, and vulcanizing the resulting laminate.

2. An improved cushioning material comprising a laminate of curled -animal [hair in the form of an approximate stereoreticulate mass bonded at the interstices by la vulcanized elastomer, a woven fabric bonded to at least one surface of said mass by said elastomer, and a substantially uniform layer of desired thickness of a foamed resilient homogeneous material bonded to said Y fabric.

3. An improved cushion material comprising a laminate of curled animal hair in the form of an approximate stereoreticulate mass bonded at the interstices by a vulcanized elastomer, cheesecloth bonded to at least one surface of said mass by said elastomer, and a substantially uniform layer of desired thickness of a foamed resilient homogeneous material bonded to said cheesecloth.

4. In a continuous process for the production of cushioning material wherein a hair pad composed of a stereoreticulate mass of hair `fibers bonded at their interstices by vulcanizable elastomeric material is provided with a shielding layer of foam material, the steps comprising bonding a woven fabric to at least one side of a hair pad with a latex of a vulcanizable elastomer, and continuously forming and bonding -a layer of a resilient substantially homogeneous foam material of desired thickness onto said fabric.

5. A process according to claim 4, wherein cheesecloth is the fabric and foam rubber is the resilient substantially homogeneous foam material employed.

References Cited in the le of this patent UNITED STATES PATENTS 1,872,846 Thiele Aug. 23, 1932 2,198,724 Schreiner Apr. 30, 1940 2,285,650 Faris et al. June 9, 1942 2,341,130 Unsworth Feb. 8, 1944 2,563,478 Mason et al. Aug. 7, 1951 2,580,202 Talalay et al. Dec. 25, l|1 2,688,152 Marco Sept. 7, 1954 2,784,773 Rowland Mar. 112, 1957 

1. A CONTINUOUS PROCESS FOR THE PRODUCTION OF HAIRFOAM RUBBER CUSHION MATERIAL WHICH COMPRISES SPREADING CURLED ANIMAL HAIR IN AN APPROXIMATE STERO-RETICULATE MASS IN THE FOAM OF A PAD OF SUBSTANTIALLY UNIFORM THICKNESS, PARTIALLY DISPERSING THROUGH ONE SURFACE OF SAID PAD A LATEX OF A VULCANIZABLE ELASTOMER, DRYING THE ELASTOMER TO A VULCANIZED CONDITION, PARTIALLY DISPERSING THROUGH THE OPPOSITE SURFACE OF SAID PAD A LATEX OF A VULCANIZABLE ELASTOMER, DRYING THE ELASTOMER TO A TACKY BUT UNVALCANIZED CONDITION, APPLYING A WOVEN FABRIC TO SAID OPPOSITE SURFACE OF SAID PAD, CONTINUOUSLY SPREADING AND LEVELLING A SUBSTANTIALLY HOMOGENEOUS FOAM LATEX ONTO SAID FABRIC TO FORM A LAYER OF FOAM RUBBER OF DESIRED THICKNESS THEREON, AND VULCANIZING THE RESULTING LAMINATE. 